Abdominal Distention in Dogs: Why Is My Dog’s Stomach Swollen?

A swollen abdomen might not seem like much of a scary problem. But it can be a sign of a life-threatening emergency. So how does one tell the difference?

Understanding potential causes and looking at the big picture comes in handy.

Distention is an enlargement or swelling from internal pressure.

Abdominal Distention in Dogs: Why Is My Dog's Stomach Swollen?

Acute or chronic?

The severity and speed of onset of your dog’s symptoms reflect the level of urgency. In other words, if it looks terrible and happens fast, you need to act quickly. In fact, with some emergencies, hours and even minutes matter.

Gradual abdominal distention

If your dog’s belly expands slowly, it doesn’t mean you don’t have to pay a visit to your veterinarian. But you don’t have to rush to a veterinary ER. In general, you can make a regular appointment with your veterinarian.

Let’s put aside obesity and pregnancy, which are self-explanatory. What other important health conditions result in an expanding belly in your dog?

Intestinal parasites

Severe infestation with intestinal parasites is most common in puppies. And yes, the puppy’s gut can harbor enough worms to cause a pot-bellied appearance.

Don’t shrug it off! Keep in mind that they steal either blood or nutrients from the puppy, and enough of them can be life-threatening.

Depending on the type of worm, other symptoms of intestinal parasites include:

  • diarrhea
  • vomiting
  • loss of appetite
  • lethargy
  • weakness
  • pale gums
Cushing’s disease

Cushing’s disease is one of the conditions that can cause a pot-belly appearance. The two contributing factors are:

  • fat shifting into the abdomen
  • weakening of abdominal muscles

Other symptoms of Cushing’s disease include:

  • increased thirst
  • increased urination/potty accidents
  • skin and coat changes
  • slow wound healing
  • weakness/sluggishness

Logically, benign or cancerous tumors anywhere within the abdomen or organs can cause abdominal enlargement.

Acute abdominal distention

Food bloat versus gastric dilatation-volvulus (GDV)

For example, your dog just broke into a bag of kibble or biscuits. Or they otherwise helped themselves to an unusual volume of food. Their stomach will expand. The creative term for that is food bloat.

It is the same thing that might happen to you after a Thanksgiving dinner. And since you’re still here reading the article, chances are your dog will also be fine.

They also might not be. So here is what the difference is.

Gastric dilatation-volvulus (GDV)

As a result of all that food, the stomach will expand–dilate. It will cause your dog discomfort and digestive upset. If you’re lucky, that might be it.

The big trouble ensues when this enlarged stomach manages to turn around on itself. Not only that it is extremely full, but everything that is in there becomes trapped. With all the digestive action in there, it will continue to expand, becoming more and more painful. Eventually, the expanded stomach will

  • cut off blood flow
  • compromise breathing
  • and the stomach can even rupture.

The medical term for it is gastric dilatation-volvulus (GDV). GDV s a dire emergency. Hours and even minutes can mean the difference between the life and death of your dog.

Some breeds are more predisposed to suffer from this problem; do you know whether your dog is on the list?

Other symptoms of bloat include:

  • pacing and restlessness
  • unproductive retching (trying to vomit with nothing coming out)
  • excessive drooling (sometimes accompanied by lip-smacking)
  • panting, heavy breathing
  • difficulty breathing
  • rapid heart rate
  • stance with extended neck and elbows pointed outward
  • pale mucus membranes
  • collapse

Source: PreventiveVet

This is the mother of all emergencies.

Without immediate veterinary care, your dog will die. The treatment involves managing shock, stabilizing your dog’s heart, and decompressing their stomach, followed by surgery.

If untreated, GDV can kill your dog within an hour.

A closet full of boogeymen


A rupture or puncture of your dog’s stomach or intestine can cause another life-threatening problem–peritonitis. Peritonitis is inflammation of the lining of your dog’s abdominal cavity. Most commonly because of bacteria that spilled out from the wound.

Peritonitis, too, is extremely painful and dangerous. It requires intensive, aggressive treatment. Some of the causes of peritonitis include:

  • abdominal injury
  • perforated intestine
  • ulcers
  • liver abscess
  • severe pancreatitis
  • a ruptured organ such as gallbladder or urinary bladder
  • cancer

Other symptoms of peritonitis include:

  • vomiting
  • diarrhea
  • loss of appetite
  • black stools
  • fever
  • lethargy
  • jaundice
  • pale gums
  • increased heart rate or arrhythmias
Internal bleeding or fluid build-up

Your dog’s stomach can swell up from internal bleeding or fluid build-up.  As you can guess, regardless of the cause, this too is scary and dangerous stuff.

Blood accumulation in the abdomen can be from trauma, a bleeding disorder, or some types of tumors. A splenic tumor, for example, can rupture and bleed into the abdomen.

Excess fluid in the abdomen can be a common side-effect of some types of

  • heart disease
  • liver disease
  • kidney disease
  • severe gastrointestinal disease
  • low blood protein levels that lead to fluid leaking out of the blood vessels

Severe uterine infection, pyometra is another life-threatening condition that can cause abdominal distention.

There are two types of pyometra – open and closed. These distinctions are about whether or not the cervix remains open.

If the cervix stays open, pus can drain out of the body. However, with closed pyometra, there is no discharge. Instead, all the pus has nowhere to drain and collects in the uterus. All along, the bacteria release toxins that enter the bloodstream.

Other signs of pyometra include:

  • vaginal discharge (with open pyometra)
  • loss of appetite
  • vomiting
  • diarrhea
  • increased thirst and urination
  • fever
  • lethargy

In conclusion, the more acute and severe your dog’s symptoms, the faster you need to see a vet.

Swollen belly rarely happens in isolation. When in doubt, err on the side of caution.

Related articles:
Symptoms To Watch For In Your Dog: Unexplained Weight Gain
Symptoms to Watch for in Your Dog: Sudden Weight Gain

Further reading:
Bloat in Dogs: What It Is, the Symptoms, and Treatment

Categories: Swollen abdomenSymptoms

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Jana Rade edited by Dr. Joanna Paul BSc BVSc

I am a graphic designer, dog health advocate, writer, and author. Jasmine, the Rottweiler of my life, was the largest female from her litter. We thought we were getting a healthy dog. Getting a puppy from a backyard breeder was our first mistake. Countless veterinary visits without a diagnosis or useful treatment later, I realized that I had to take Jasmine's health care in my own hands. I learned the hard way that merely seeing a vet is not always enough. There is more to finding a good vet than finding the closest clinic down the street. And, sadly, there is more to advocating for your dog's health than visiting a veterinarian. It should be enough, but it often is not. With Jasmine, it took five years to get a diagnosis. Unfortunately, other problems had snowballed for that in the meantime. Jasmine's health challenges became a crash course in understanding dog health issues and how to go about getting a proper diagnosis and treatment. I had to learn, and I had to learn fast. Helping others through my challenges and experience has become my mission and Jasmine's legacy. I now try to help people how to recognize and understand signs of illness in their dogs, how to work with their veterinarian, and when to seek a second opinion. My goal is to save others the steep curve of having to learn things the hard way as I did. That is the mission behind my blog and behind my writing. That is why I wrote Symptoms to Watch for in Your Dog, which has turned out being an award-winning guide to dog owners. What I'm trying to share encompasses 20 years of experience. Dr. Joanna Paul BSc BVSc is our wonderful sponsor and has been kind to edit and fact-check my important articles.

  1. Excellent info. Sadly, when my always healthy and energetic Husky, Bandit, suddenly collapsed I knew it was what her older brother was lost to, a bleeding spleen and hemangiosarcoma…so when we arrived at the vet, the vet said her belly had become distended and was full of fluid and blood, and no warning. We had to let sadly her go…that one was shock. She was always our super healthy one. Thought we’d have her well into old age. Distended belly is very serious…will be Pinning to share this info.

  2. “Keep in mind that they steal either blood or nutrients from the puppy” Now this stopped me in my tracks. You simply don’t realise they are not just ‘a few worms’ you can get rid of they are putting a puppy at risk! THAT is frightening.

    This post is eseential reading and I am sharing this as much as I can. I am sure most people do not realise so many things can go wrong with a swollen tummy as the first indication.

  3. I knew about bloat, but not all of these issues. I’ll remember to take my dogs to the vet immediately if they have abdomen swelling!

  4. This is great information on the importance of identify dog stomach bloat and seeking vet attention. I’m always paying attention to my dog’s, Henry’s stomach, since he has a sensitive stomach. What to look for and the urgency to seek attention is really important. While Henry generally likes food, I’ve been surprised that he seems to stop eating when he’s full. He’s the first dog I’ve been around who won’t eat until he has food bloat or the equivalent of human “Thanksgiving guts” if given the chance. I wish I had that gene. 😉

  5. These are all so scary, especially since most require immediate Vet care. Bloat is the thing that has always scared me so much. I’m always looking at my dog’s belly to make sure it looks normal. Thanks for sharing this info.

  6. I didn’t realize abdomen swelling was caused by so many issues. I’ve heard of dogs dealing with Cushing’s or worms but did not know about some of these other serious conditions. Thanks for sharing.

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